1. Field of the Invention
The present invention relates to inflatable restraints. More specifically, the present invention relates to an inflatable restraint module that is lighter and less expensive than conventional airbag modules.
2. Technical Background
The inclusion of inflatable safety restraints, or airbags, is now a legal requirement for many new vehicles. In addition to this, inflatable airbags enjoy widespread acceptance for use in motor vehicles and are credited with preventing numerous deaths and injuries. Some studies estimate that the use of frontally placed airbags reduces the number of fatalities in head-on collisions by 25% among drivers using seat belts and by more than 30% among unbelted drivers. Other research suggests that in a frontal collision, the combination of a seat belt and an airbag can reduce serious chest injuries by 65% and serious head injuries by up to 75%. These numbers, and the thousands of prevented injuries they represent, demonstrate the life-saving potential of airbags and the need to encourage their use, production, and development.
As a result, in part, of benefits such as those described above, automakers are now required to install airbags in most new vehicles sold in the United States. Furthermore, many automobile manufacturers have turned airbag technology into a marketing tool. Enticed by the promise of added safety, many vehicle purchasers seek out vehicles with sophisticated airbag systems.
Airbags are often installed in the steering wheel and in the dashboard on the passenger side of a vehicle. In the event of an accident, an accelerometer situated within the vehicle measures the abnormal deceleration caused by the accident and triggers the expulsion of expanding gases from an inflator into each of the airbags. The expanding gases rapidly fill the airbags, which immediately inflate in front of the driver and passenger to protect them from impacts against the windshield, dashboard, or steering wheel.
As a result of the success of front-installed airbags, other airbags designed to protect occupants in various types of vehicular collisions have been developed. For instance, side impact airbags, often in the form of inflatable curtains, were developed in response to the need for protection from impacts in a lateral direction, or against the side of the vehicle. Such curtains are placed along the side of a vehicle in places such as the ceiling or roof rails. An inflatable curtain may be composed of one or more separately inflated cushions that protect individual passengers in different positions within the vehicle.
Automobile manufacturers may install airbags in their vehicles by securing an airbag module to an appropriate location within the vehicle and connecting an inflator within the module to an accelerometer of the vehicle. The airbag module may include structures for securing the module within the vehicle and an interface for connecting the inflator to the accelerometer.
One type of conventional airbag module may include an inflatable cushion. The inflatable cushion may have two openings for receiving the inflator. However, the inflator cannot be placed immediately adjacent to the inflatable cushion. If so, heat generated during activation of the inflator could damage the cushion and prevent proper deployment.
To avoid damage to the cushion, a diffuser is often interposed between the inflator and the cushion. The diffuser surrounds the inflator and separates the inflator from the cushion. The diffuser is often made from metal. Consequently, the diffuser is quite heavy. Also, the diffuser typically includes a number of openings to allow gas from the inflator to move from the inflator into the cushion. As such, the diffuser is intricate and is made by a relatively complex manufacturing process. This process can become quite expensive, particularly when a large number of airbag modules are manufactured. The diffuser may also include protrusions for securing and orienting the diffuser within a canister, again increasing the complexity of the airbag module.
The canister protects the inflatable cushion and inflator and may be used to secure the airbag module to the vehicle. Although various configurations exist, the protrusions generally pass through apertures in the inflatable cushion and interlock with the canister. Unfortunately, the apertures increase the cost and complexity of manufacturing the cushions.
The canister must also include openings, mechanisms, and/or structures for interlocking with the protrusions of the diffuser. These interlocking mechanisms are often complex and intricate. The manufacturing process must be precise to ensure a smooth interaction between the protrusions and the locking mechanisms. Thus, the manufacturing costs are high.
In view of the foregoing, it would be an advancement in the art to provide an airbag module having lighter and less intricate components. It would be a further advancement in the art to provide an airbag module that is less expensive to manufacture than conventional airbag modules.
The apparatus and methods of the present invention have been developed in response to the present state-of-the-art, and, in particular, in response to problems and needs in the art that have not yet been fully resolved by currently available airbag modules. To achieve the foregoing, and in accordance with the invention as embodied and broadly described in the preferred embodiments, an inflatable restraint module that is lighter and less expensive to manufacture than conventional airbag modules is disclosed.
The inflatable restraint module may include an inflator that generates gas or foam to inflate an inflatable cushion. The gas or foam may exit the inflator through one or more gas exit ports. The inflator may be generally cylindrical in shape and have a first and a second end. The first end of the inflator may include inclined threads. A mating nut may be attached to the incline threads. The second end of the inflator includes an expanded portion.
The inflatable restraint module may also include a heat shield disposed around the inflator. The heat shield is shaped to surround the inflator. For instance, if an inflator is cylindrical in shape, the heat shield may be a rectangular piece of fabric that can be positioned around the inflator. The heat shield may be made from various materials, including a heat-resistant fabric.
The heat shield does not necessarily encompass the entire inflator. Instead, the heat shield, when disposed around the inflator, may define a gap. The exit gas ports of the inflator may be aligned with the gap in the heat shield.
The inflatable restraint module may include an inflatable cushion disposed around the heat shield and inflator. More specifically, the cushion may include a loop defining two orifices. The orifices may be shaped to receive an inflator such that the cushion surrounds the inflator. The cushion may also include an expandable portion that expands when a foam or gas from the inflator is rapidly injected into the inflatable cushion.
The inflatable restraint module may also include a chamber positioned around the inflator, heat shield, and loop of the cushion. The chamber may be generally cylindrical and may be shaped to receive the inflator, heat shield, and loop. More specifically, the chamber may include an interior compartment having two open ends. Thus, the loop of the cushion having the inflator and heat shield disposed therein is positioned within the interior compartment. The chamber is shorter than the inflator such that the first and second ends of the inflator may protrude out of each of the open ends of the chamber when an inflator is positioned in the chamber.
The open ends of the interior compartment should be sufficiently large, such that the inflator, heat shield, or both may be inserted through one of the open ends into the interior compartment. Of course, the open ends may be partially enclosed and still permit an inflator to be inserted into the interior compartment.
An opening may be formed in the chamber. The loop of the cushion extends from the interior compartment through the opening of the chamber. The expandable portion of the cushion is positioned in a folded state on a lip of the chamber. Accordingly, the opening may be configured in various shapes to achieve this purpose. The gap of the heat shield may be aligned with the opening in the chamber so that gas may rapidly exit the inflator through the gap of the heat shield into the inflatable portion of the cushion.
The chamber may also include an outward extension. The extension may be positioned proximate the opening and projects away from the opening. The extension is coupled to the cushion. In this embodiment, the extension may be coupled to the cushion by attachment to the cushion. More specifically, a portion of the cushion is attached to the extension of the chamber. The portion of the cushion may be sewn to the extension. Alternatively, the portion may be attached to the extension using adhesives, rivets, a nut and bolt, or the like. Being attached to the extension, the portion of the cushion is kept away from the opening in the chamber and, as a consequence, is kept away from the inflator. If the portion of the cushion were not kept away from the inflator, the cushion could be damaged by heat generated by the inflator during inflation. Thus, the extension is shaped to keep a portion of the cushion away from the opening. The extension may be configured in various ways to achieve this purpose.
The chamber is simple in design and may be made from various materials, including plastic or metal. When made from plastic, the chamber is very light and inexpensive to manufacture.
The inflatable restraint module may also include a canister at least partially disposed around the inflator, heat shield, cushion and chamber. More specifically, the canister may include an interior region in which the inflator, heat shield, cushion and chamber may be positioned. The canister may also define an open side through which the cushion and chamber may be inserted into the interior region. The cushion may deploy through the open side of the canister.
The canister also includes a first and a second mouth. The first and second mouths may be formed in opposing ends of the canister. The first and second mouths may be shaped and positioned so that the first end of the inflator is disposed within the second mouth of the canister, and a second end of the inflator is disposed within the first mouth of the canister. The first mouth is shaped to receive the inflator so that the inflator may be inserted into the canister through the first mouth.
A mating nut is attached to the inclined threads on the first end of the inflator. The mating nut is wider than the second mouth of the canister. As stated above, the second end of the inflator includes the expanded portion that is wider than the first mouth of the canister. Thus, the canister is positioned between the expanded portion of the inflator and the nut, which is attached to the inflator. The nut is tightened down on the inclined threads so that the nut and expanded portion are pulled towards each other to secure the inflator within the canister. When secured in the canister and positioned in through the loop of the cushion, the inflator aids in securing the cushion to the canister, such that the cushion is tethered to the inflatable restraint module at the time of inflation.
Like the first embodiment, a second embodiment of the inflatable restraint module includes a cushion, inflator, and heat shield. As will be explained below, the second embodiment also includes a chamber and a canister which may be slightly different than those of the first embodiment. The second embodiment also includes a cover that is not used in the first embodiment of the inflatable restraint module.
In the second embodiment, just as in the first embodiment, a heat shield is positioned around the inflator. The heat shield and inflator are positioned within a loop of the cushion. The loop of the cushion is situated within an interior compartment of a chamber. The cushion extends out of the interior compartment through an opening in the chamber. An expandable portion of the cushion may be folded and placed on a lip of the chamber.
As in the first embodiment, an outward extension of the chamber is coupled to the cushion. More specifically, a portion of the cushion is attached to the outward extension of the chamber. The outward extension may be situated proximate the opening and projects away from the opening. Attachment of the portion of the cushion to the extension keeps the portion of the cushion away from the opening of the chamber and the inflator to prevent damage to the cushion at the time of inflation.
In the second embodiment, the inflator, cushion, and chamber are also positioned within an interior region of a canister. The inflator, cushion, and chamber may be inserted into the interior region of the canister through an open side of the canister.
Like the first embodiment, the second embodiment also includes a canister having a first and second mouth. A first end of the inflator may be positioned within the second mouth of the canister, and a second end of the inflator may be situated within the first mouth of the canister. The second end of the inflator includes an expanded portion that is wider than the first mouth of the canister. As with the first embodiment, a mating nut, which is wider than the second mouth, may be attached to inclined threads on the first end of the inflator to secure the inflator within the canister.
Unlike the first embodiment, the second embodiment includes a cover that extends from the extension of the chamber, across the open side of the canister, and is attached to the canister. The cover is shaped to cover the cushion and thus to prevent damage to the cushion. The cover may be integrally formed with the extension of the chamber or may be attached to the chamber. For instance, the cover may be sewn to the extension. Alternatively, adhesives, rivets, or a nut and bolt may be used to attach the cover to the extension.
The cover is also attached to the canister. Again, various techniques may be used to do so. For instance, the cover may include a set of tabs that interlock with mating apertures in the canister.
At the time of inflation, the cushion deploys through the cover. Thus, the material from which the cover is made may, for instance, include frangible seams so that the cover does not impede deployment of the inflatable cushion.
Like the first embodiment, a third embodiment includes an inflator, heat shield, cushion, and canister. As will be explained below, the third embodiment includes a chamber which is slightly different from the chamber of the first embodiment and further includes a cover that is different than the cover of the second embodiment.
In the third embodiment, just as in the first embodiment, a heat shield is positioned around the inflator. The heat shield and inflator are positioned within a loop of the cushion. The loop of the cushion is situated within an interior compartment of the chamber. The cushion extends out of the interior compartment through an opening in the chamber. An expandable portion of the cushion may be folded and placed on a lip of the chamber. In the third embodiment, the inflator, cushion, and chamber are also positioned within an interior region of the canister. The inflator, cushion, and chamber may be inserted into the interior region of the canister through an open side of the canister.
Like the first embodiment, the third embodiment also includes a canister having a first and second mouth. The inflator is positioned in the canister such that a first end of the inflator is positioned within the second mouth of the canister, and a second end of the inflator is situated within the first mouth of the canister. The second end of the inflator includes an expanded portion that is wider than the first mouth of the canister. As with the first and second embodiments, a mating nut, which is wider than the second mouth, may be attached to inclined threads on the first end of the inflator to secure the inflator within the canister.
The cushion is coupled to the outward extension of the chamber. However, unlike the first embodiment, the cushion is coupled to the outward extension by attachment to a cover, which is attached to the outward extension. More specifically, a portion of the cushion is attached to a cover and the cover is attached to the outward extension of the chamber to keep the portion of the cushion away from the opening of the chamber and the inflator to prevent damage to the portion of the cushion at the time of inflation. The cover may be attached to the cushion using various techniques. For instance, the cover may be sewn to the cushion.
The cover may be attached to the extension using various techniques. For example, a first set of apertures in the cover may mate with a set of tabs on the extension of the chamber. The cover of the third embodiment then wraps around, or surrounds, the chamber and the expandable portion of the cushion. As explained above, the inflator, heat shield, and loop of the cushion are disposed within the chamber.
After being wrapped around the chamber and expandable portion of the cushion, the cover attaches once again to the extension. For instance, tabs on the extension may mate with a second set of apertures in the cover. Of course, various techniques may be used to attach the cover to the extension. For instance, the cover may be sewn to the extension. Alternatively, rivets, a nut and a bolt, or adhesives may be used to attach the cover to the extension. The cover may be sewn to the inflatable cushion. The cover may be made from various materials, including fabrics and plastics, as will be understood by those skilled in the art.
In view of the foregoing, the inflatable restraint module provides substantial advantages over conventional airbag modules. The individual components of the inflatable restraint module are simple in design and, as a consequence, are less expensive to manufacture than conventional module components. Many of the components may be made from plastic or fabric rather than metal, further diminishing the cost and weight of the module.
These and other advantages of the present invention will become more fully apparent from the following description and appended claims, or maybe learned by the practice of the invention as set forth hereinafter.